NEW YORK, June 19 (Reuters) - Dan Ivascyn, the group chief investment officer at bond giant Pacific Investment Management Co, on Tuesday said it is a "relatively dangerous environment for investors" because of political uncertainty making stretched market valuations more vulnerable.

"It's about trying to limit the downside when fear returns to the market and volatility rises," Ivascyn said in a telephone interview.

U.S. stocks opened lower on Tuesday as President Donald Trump's latest threat to impose duties on additional Chinese goods heightened worries that tit-for-tat tariffs could spiral into a trade war. (Reporting By Jennifer Ablan Editing by Chizu Nomiyama)